select the three questions that are best categorized as statistical questions.

A) how many books are there in the library?
B) how many letters are in the alphabet?
C) what is the height of the empire state building?
D) how tall are the members of the basketball team?
E) how long does each roller coaster ride in the amusement park last?
F) what is the average number of students in each class at lincoln high school?